Ms Price, of Arael View in Cwmtillery, said she believed her daughter was with a man she met three months ago but beyond that has no idea where she might have gone on from Newport.

She said this was the first time the mum has disappeared. Her children are being cared for by their father.

And she said: "Karla got a flat opposite me and we never heard anything. And we phoned the social services about the welfare of the baby and then it went from there then."

The missing woman is described as 5ft 2in tall, with dark, dyed shoulder length hair. She is slim although she is pregnant, and could have been seen wearing a pink waterproof hoody.

Karla is the youngest of three siblings. She has a brother, Shaun, 30, and a sister, Leanne, 31.

And Leanne took to Facebook yesterday to thank people for sharing Gwent Police’s message about her sister on their page. Yesterday afternoon, the police's message had been shared more than 2,400 times.

She wrote: “On behalf of me and my mother we would just like to say thank you to everyone for taking the time to share this post just hope we find her before it’s too late for her and the baby xxx.

“If anyone knows anything let us know. My mother’s very worried xx.”

Gwent Police said on Monday that they are concerned for Ms Price’s welfare because she is pregnant and because of “the time she has been missing”.

Anyone who might have seen Ms Price is asked to call the police on 101 and quote log number 148 2/5/14.